CA2199984A1 - Robotic arm assembly - Google Patents

Abstract

A robotic arm assembly (1) includes a support structure (3) in which an arm (2) is pivotable and which accommodates lineal and rotational drive means to enable lineal or rotational and pivotal movement of said arm (2) and with the overall construction providing a readily cleanable surface suitable for use in harsh environments.

Description

wog6/08347 ~ q ~ ~ ~ 8 4 PCT~NZ9SJ00085 ROBOTIC ARM ASSEMBLY
Bac}~4 ~ o~.d of the Invention The present invention relates to improvements in and relating to a robotic arm assembly.

The term "robot" is used throughout this specification in respect of any type of controllable manipulator. Robots have assumed a major role in industl-y- peïfoïmins tasks ranging from the automatic welding of car bodies to the automatic dressing of animal carcasses.

In applications within ~ood processing, pharmaceutical manufacturing, etc, a major consideration is the ability for the robot to avoid becoming unhygienic such as by it capturing food product particles or dust for example and for it to be kept clean such as by washing. In many food processing environments such as in abattoirs, the conditions can be extremely harsh characterised by high humidity, high temperature water and carcass particles and blood. Any machinery working in such environments will inevitably require frequent cleaning in order to maintain a requisite standard of hygiene.

At the present time robots working in harsh environments have required specially designed protective W096/08347 ~ ~ 9 ~ ~ ~ 4 PCT~Z95/0008S

covers as their designs as such have not facilitated their being kept clean.

It is thus an object of the present invention to provide a robotic arm assembly which is able to work in harsh environments but still be able to be kept clean or which at least will provide the public with a useful choice.

Further objects of this invention will become apparent from the following description.

BRIEF SUMMARY OF THE lNv~NLlON

According to one aspect of the present invention there is provided a robotic arm assembly comprising:

(a) at least one substantially smooth surfaced arm having manipulating means at least at one free end thereof;

(b) an enclosed or enclosable support assembly connected with said arm enabling said arm to pivot relative thereto;

(c) lineal and rotational drive means being provided for said arm and said support assembly so as to W096/98347 2 ~ 8 4 PCT~

provide a required number of degrees of freedom of movement;

whereby said support assembly and said arm combine to form a substantially enclosed construction presenting substantially readily cleanable external surfaces.

According to a further aspect of the present ir.ventior, there is provided a robotic ar~ asse~iy as defined immediately above wherein said support means includes an inner enclosed plate assembly adapted to accommodate thereon said rotational and lineal drive means.

Further aspects of this invention which should be considered in all its novel aspects will become apparent from the following description given by way of example of possible embodiments thereof and in which reference is made to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fiqure 1 shows a rear, diagrammatic view, of a robotic arm assembly according to one possible embodiment of the invention;

W096/08347 ~ 8 ~ PCT~llOC ~

Fiqure 2 shows a front view of the assembly of Figure l;

Fiqure 3 shows very diagrammatically a left side view of the assembly of Figures 1 and 2;

Fiqure 4 shows very diagrammatically a right side view of the assembly of the preceding Figures;

Fiqure 5 shows partial and cross sectional view of the assembly according to one possible embodiment of the invention but with the telescopic arm omitted;

Fiqure 6 shows the support plate assembly for use in a preferred embodiment of the invention;

Flqure 7 shows diagrammatically a cross sectional view through the telescopic arm according to one possible embodiment of the invention.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS

As mentioned above, harsh environments involving temperature, water or other liquids including blood, humidity, dirt, air borne particles of food or processed W~96/08347 ~ 9 8 4 PCT~ ~5S00085 debris make it difficult for machinery such as robots to be kept clean and working. In food processing environments the need to maintain hygiene is of course - paramount.

The present invention has therefore sought to achieve a robotic arm assembly which is suited to working in a harsh environment but which can be readily cleaned such as by washing down with high pressure hoses with water at high temperatures. Referring to Figures 1 to 4 particularly, the robotic arm assembly is referenced generally by arrow 1 and is shown comprising a telescopic arm 2 accommodated for pivotal movement in a direction indicated by arrows A within housing 3.
Only one arm is shown but a plurality of arms 2 is envisaged. The housing 3 is shown provided, front and rear, with an arcuate shell housing 4 to accommodate the pivoting movement of the arm 2. In the Figures, the front end 5 of the arm 2 is shown in its raised position within the front shell 4 in the housing 3 but as required, the arm 2 can be pivoted so as to lower the front end 5 so that the rear end 7 (see Figure 1) then moves towards accommodation in the rear shell 4. The front end 5 of the arm 2 will suitably include, or be attachable to, the appropriate tooling such as a cutting, welding or gripping tools or the like with the W096/08347 PCT~Z9S/00085 ~ ~ ~ 9 ~ 8 4 ~

capability of rotating the tool preferably through 360~
in clockwise or anti clockwise directions as indicated by the arrows B. In the drawings the tool is shown by way of example as a gripping means 32.. The arm 2 may suitably be able to pivot about one of the downwardly depending legs 8 of housing 3 about a suitable pivot point 6 indicated in profile very diagrammatically in Figure 2. A housing 9 will suitably accommodate a motor for ccntrolling the pivoting of the arm 2 and to also provide a drive for one or more of the rotational or lineal movements required of the assembly 1.

The assembly 1 may suitably comprise a polar configuration mountable on a horizontal linear axis and, depending on its required application, in one embodiment providing for example a total of four degrees of freedom of movement (DOF) which in the illustrated embodiment may be identified as follows:

Axis movements:
Axis Type Range 1. Main Travel Linear 60Omm 2. Main Arm Revolute goo 3. (Telescopic arm) Linear 300mm 4. (Wrist) Revolute 360~

W096/08347 ~ 9 8 4 PCT~ ~5~00085 The number and disposition of the above axes and the ranges of motion are of course by way of example only and will depend on a particular application for which the robotic arm assembly is required.

Alternative mixtures of revolute and linear axes are of course possible forming part of the present invention.

To accommodate the lineal movement of the support assembly 3 with the arm 2 a concertina housing lO is shown provided on both sides of the housing 3 which is then able to expand or contract in accommodating the linear movement. The housings 10 are shown closed off by respective plate members 11.

The housing 3, plates 11, telescopic arm 2 and housings 9 and 10 thus combine to provide a very simple design which presents a minimal number of surfaces required to be cleaned and those that are present can be readily washed down such as with a high pressure hose.
To further facilitate cleaning stainless steel and/or polished aluminium and/or plastics, may be used for any exposed surfaces. In a preferred embodiment of the invention the telescopic arm will preferably comprise a pair of co-axial stainless steel tubes providing a W096/08347 ~ 8 ~ PCT~S/0008S

stepped portion 12 (see Figure 2). The concertina structures 10 may suitably be of some plastic material which provides both a flexible and a washable surface.

In Figure 5, a part cross sectional view of the assembly 1 illustrates the drive motor 20 positioned within the housing 9 and mounted to the side of a plate 18 which is shown in greater detail in Figure 6. The plate 18 includes provision at 19 For a suitable gear box such as an harmonic drive gear box connectable to the drive motor through a suitable cantilevered arrangement. A drive wheel 20 is shown providing a drive through a suitable belt to a recirculating ball screw or the like 21 engageable with a fixed threaded shaft 22 so as to provide for the lineal motion of the assembly 1.

A pair of parallel linear bearings 23 are shown engaging with a horizontal support member 24 which will provide the required support for the assembly external thereto as it traverses horizontally.

The plate 18 thus provides a main vertical support for the assembly 1 and the supporting link of the arm 2 to the horizontal carriage way 24. The plate 18, which W096/08347 ~ 8 ~

may be machined from solid metal such as aluminium is also supporting the linear axis motor and the lead screw actuation system.

The overall support for the assembly 1, which may in any particular embodiment weigh in the region of lOOkg, can be by means for example of a suspension from a cantilever from a chain superstructure; such an arrangement avoids any suppcrt from below which could affect the ability o~ cleaning beneath the robotic arm assembly 1.

It is seen therefore that the plate assembly 18 is able to achieve a combination of functions in providing the support for the drive and drive connections to the assembly 1 thus enabling the single cover assembly 3 to provide the simple yet effective pivotal support for the arm 2.

In Figure 7 the arm 2 is shown with its front manipulator end 5 at the front end of an inner tube 2A
telescopically slideable within an outer tube 2B along a shaft 25. The telescopic movement can be controlled by means of a screw/threaded rod arrangement, piston and cylinder hydraulic arrangement, or the like.

W096/08347 ~ ~ g ~ ~ 8 4 PCT~Z95~-Y~

In the preferred embodiment as shown a beariny assembly may comprise a linear bearing 31 at one end and a nickel impregnated Teflon (Registered Trade Mark) bearing 30 or the like at the other end. This may avoid the need for exact tolerances in the manufacture of the arm 2 and hence reduce costs.

A further aspect of one embodiment of the present invention relates to the mar.u acture o~ the tubes 2A, 2B. Their mass and stiffness are very important but normal construction can be difficult. Accordingly software routines may be written for a CAD package which automatically produces the flat developments of the intersection of the tubes and these drawings are exported as DXF files. The DXF files may then be read by a laser cutting machine or the like to accurately cut the shapes from sheet material. The shapes may then be folded or rolled and fitted into special jigs where they are welded together. The welded joints can then be ground and polished.

It is thus seen that the present invention provides a robotic arm assembly which has a substantially compact design resulting in a minimum of exposed surfaces but which surfaces can substantially be provided so as to be readily washable. The assembly is therefore adapted for WO 96/08347 PCII~Z95,'~- D~C
~ 8 ~

use in environments where hygiene considerations are important. The compact design also enables a relatively small number o~ joints to be required between the various components having external surfaces and where any exposed joints are present these may be readily sealed so as to prevent the ingress of water or other material or where such ingress may be unavoidable the compact design can ensure that this will not adversely affect the operation o~ the asser~ly.

Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the scope or spirit of the invention as defined in the appended claims.

Claims (9)

Claims:

1. A robotic arm assembly comprising:
(a) at least one substantially smooth surfaced arm having manipulating means at least at one free end thereof;

(b) an enclosed or enclosable support assembly connected with said arm enabling said arm to pivot relative thereto;

(c) lineal and rotational drive means being provided for said arm and said support assembly so as to provide a required number of degrees of freedom of movement;

whereby said support assembly and said arm combine to form a substantially enclosed construction presenting substantially readily cleanable external surfaces.

2. A robotic arm assembly as claimed in Claim 1 wherein said support assembly includes an inner enclosed plate assembly adapted to accommodate thereon said rotational and lineal drive means.

3. A robotic arm assembly as claimed in Claim 2 wherein said inner enclosed plate assembly provides a supporting linkage between said arm and a horizontal carriageway.

4. A robotic arm assembly as claimed in any one of the preceding claims wherein said support assembly includes an arcuate shell housing to accommodate the pivoting movement of the arm.

5. A robotic arm assembly as claimed in Claim 4 wherein said housing includes a downwardly depending leg having a pivot point about which said arm pivots.

6. A robotic arm assembly as claimed in any one of the preceding claims wherein a concertina housing extends on either side of said support assembly to accommodate said lineal movement.

7. A robotic arm assembly as claimed in claim 2 or claim 3 or any one of claims 4 to 6 when dependent on claim 2 or claim 3 wherein a transmission means connects said drive means to a rotatable screw means engageable with a threaded shaft to provide said lineal movement of a horizontal support member.

8. A robotic arm assembly as claimed in any one of the preceding claims wherein said arm comprises at least a pair of telescopic tubes controllably movable to provide relative movement therebetween.

9. A robotic arm assembly substantially as herein described with reference to the accompanying drawings.